This invention relates to the oligomerization, polymerization and copolymerization of substituted and unsubstituted xcex1-methylene-xcex3-butyrolactones (MBLs) using cobalt chain transfer catalysts to control molecular weight.
The free radical polymerization of xcex1-methylene-xcex3-butyrolactone, as well as its copolymerization, is described by M. K. Akkapeddi, Polymer, vol. 20, 1979, pp. 1215-1216, and Japanese Patent Application 9012646. However, no catalysts were used and no end-group analyses were disclosed in any of these references.
It is known to use various cobalt complexes (e.g., cobaloximes) as chain transfer catalysts (CTC) to provide macromonomers which provide terminal double bonds for use in polymeric products. See commonly owned U.S. Pat. Nos. 5,310,807, 5,362,813, 5,412,039, 5,502,113, and 5,587,431 and WO 9525765. However, no examples of aromatic group formation during catalysis is shown as in the present invention.
The use of cobalt chain transfer catalysts to control the molecular weight of oligomers and polymers is known. U.S. Pat. Nos. 5,602,220, 5,770,665 and 5,684,101 as well as WO 9613527 disclose this control, but do not teach xcex1-methylene-xcex3-butyrolactones or aromatic group formation during catalysis. Commonly owned U.S. Pat. No. 5,726,263, and application Ser. Nos. 08/818,860, 09/193,701 and 08/912,593 also disclose this control, but again, do not disclose this particular monomer or aromatic groups formed during catalysis.
This invention relates to a process for oligomerizing or polymerizing or copolymerizing (xcex1-methylene-xcex3-butyrolactones to poly(xcex1-methylene-xcex3-butyrolactones) having controlled molecular weight and aromatic functionality, wherein the process comprises contacting an xcex1-methylene-xcex3-butyrolactone, optionally in the presence of a comonomer, with a free radical initiator and a cobalt chain transfer catalyst, said xcex1-methylene-xcex3-butyrolactone having a structure: 
wherein R1 and R2 are each independently selected from the group (I) consisting of H, xe2x80x94CH(O), xe2x80x94CN and halogen, and from the group (II) consisting of xe2x80x94C(O)OR5, xe2x80x94C(O)NR6R7, xe2x80x94CR8(O), xe2x80x94C(O)OC(O)R9, xe2x80x94C(O)NR10COR11, xe2x80x94OC(O)R12, xe2x80x94OR13, alkyl, substituted alkyl, aryl and substituted aryl; wherein when R1 or R2 are selected from group (II), R1 and R2 may optionally form a cyclic structure; R5, R6, R7, R8, R9, R10, R11, and R12 are H, alkyl, aryl, substituted alkyl or substituted aryl; R13 is alkyl, aryl, substituted alkyl or substituted aryl; and wherein the alkyl and substituted alkyl are C1-C12, and the substituents on the substituted alkyl or substituted aryl contain no functionality which would substantially interfere with free radical polymerization; said process carried out at a temperature from about room temperature to about 240xc2x0 C., optionally in the presence of a solvent.
This invention further relates to the cooligomerization of xcex1-methylene-xcex3-butyrolactones with comonomers selected from the group consisting of acrylonitrile, methacrylonitrile, vinyl methyl ketone, 4-chlorostyrene, 4-chloromethylstyrene, 2,3-dimethylstyrene, 3,4-dichlorostyrene, 4-bromostyrene, 4-hydroxystyrene, 4-methoxystyrene, 4-oxymethylstyrene, 4-bromomethylstyrene, 4-styrenesulfonic acid, sodium salt of 4-styrenesulfonic acid, 4-styrenesulfonyl chloride, methyl acrylate, ethyl acrylate, propyl acrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, dodecyl acrylate, glycidyl acrylate, acrylamide, N,Nxe2x80x2-dimethylacrylamide, bisacrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, acrylic acid, sodium salt of acrylic acid, zinc salt of acrylic acid, acryloyl chloride, [2-(acryloyloxy)ethyl]trimethyl ammonium chloride, 2-ethyloxyethyl acrylate, 2-(N,Nxe2x80x2-dimethylamino)-ethyl acrylate, methacryloyl chloride, methacrylic anhydride, acrylic anhydride, [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride, 2-(methacryloyloxy)ethyl methacrylate, 2-(methacryloyloxy)ethylacetoacetate, [2-(methacryloyloxy)propyl]-trimethyl ammonium chloride, vinylchloride, 4-vinylbenzoic acid, vinyl acrylate, vinyl methacrylate, vinyl chloroformate, vinyl pyridine, benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, methacrylonitrile, alpha methyl styrene, trimethoxysilylpropyl methacrylate, triethoxysilylpropyl methacrylate, tributoxysilylpropyl methacrylate, dimethoxymethylsilylpropyl methacrylate, diethoxymethyl-silylpropylmethacrylate, dibutoxymethylsilylpropyl methacrylate, diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropyl methacrylate, dibutoxysilylpropyl methacrylate, diisopropoxysilylpropyl methacrylate, isopropenyl butyrate, isopropenyl acetate, isopropenyl benzoate, isopropenyl chloride, isopropenyl fluoride, isopropenyl bromide, itaconic acid, itaconic anhydride, dimethyl itaconate, methyl itaconate, N-tert-butyl methacrylamide, N-n-butyl methacrylamide, N-methyl-ol methacrylamide, N-ethyl-ol methacrylamide, isopropenylbenzoic acid (all isomers), diethylamino alphamethylstyrene (all isomers), para-methyl-alpha-methylstyrene (all isomers), diisopropenylbenzene (all isomers), isopropenylbenzene sulfonic acid (all isomers), methyl 2-hydroxymethylacrylate, ethyl 2-hydroxymethylacrylate, propyl 2-hydroxymethylacrylate (all isomers), butyl 2-hydroxymethylacrylate (all isomers), 2-ethylhexyl 2-hydroxymethylacrylate, isobornyl 2-hydroxymethylacrylate, methyl 2-chloromethylacrylate, ethyl 2-chloromethylacrylate, propyl 2-chloromethylacrylate (all isomers), butyl 2-chloromethylacrylate (all isomers), 2-ethylhexyl 2-chloromethylacrylate, isobornyl 2-chloromethylacrylate, vinylpyrrolidone, and substituted xcex1-methyl-xcex3-butyrolactones of the following structure: 
where R1 and R2 are as defined above, and R3 and R4 are also independently selected from group (I) and group (II), as defined above.
This invention further relates to the products of the processes described.
The use of catalytic chain transfer catalysts in the free radical polymerization of vinylic monomers is widely known and well reflected in the art. See, for example, U.S. Pat. Nos. 5,587,431, 5,362,813, 5,324,879, 5,028,677, and 4,526,945, all incorporated by reference herein. Conducted by cobalt complexes of a very specific structure, the catalysis allows molecular weight (MW) to be effectively controlled. It is also important that these reactions lead to formation of polymers and oligomers with a terminal double bond strictly one bond per polymer molecule (more than 95% ) as found in T. P. Davis, D. M. Haddleton, S. N. Richards., J. M. S.xe2x80x94Rev. Macromol. Chem. Phys., C34 (1994) 243.
A new monomer, xcex1-methylene-xcex3-butyrolactone, represented in an unsubstituted form is shown in I below, 
Surprisingly it was found that this monomer behaves differently from acrylates or methacrylates, its structural analogues. In case of methacrylates cobalt-catalyzed chain transfer provides polymer with a double bond. Unexpectedly, polymerization of xcex1-methylene-xcex3-butyrolactone under the same conditions gave an oligomer which have aromatic functionality, as indicated by 7.1-7.4 ppm resonance in the proton NMR spectrum, but no isolated double bonds. The NMR data suggests that the cobalt catalyst causes isomerization of the oligomer and polymer in addition to regular hydrogen abstraction from the propagating radical. Therefore, the resulting oligomers have aromatic functionality but no isolated double bonds.
Hence, cobalt chain transfer catalyst provides not only molecular weight control in xcex1-methylene-xcex3-butyrolactone polymerization as shown in the examples herein, but also, unusual functionalization,xe2x80x94that is to say aromatic functionalization of the polymeric product.
Until recently, wide usage of xcex1-methylene-xcex3-butyrolactone was restricted by its high cost. In recent years interest in polymers made using xcex1-methylene-xcex3-butyrolactone has increased as economically attractive synthetic routes to xcex1-methylene-xcex3-butyrolactone have been developed. Alpha-methylene-xcex3-butyrolactone is relatively easy to polymerize and copolymerize by free radical mechanism as described herein, to yield polymers with relatively higher glass transition temperatures, Tg. The homopolymer has a Tg of about 200xc2x0 C.
Alpha-methylene-xcex3-butyrolactones have the general formula 
wherein
R1 and R2 are each independently selected from the group (I) consisting of H, xe2x80x94CH(O), xe2x80x94CN and halogen, and from the group (II) consisting of xe2x80x94C(O)OR5, xe2x80x94C(O)NR6R7, xe2x80x94CR8(O), xe2x80x94C(O)OC(O)R9, xe2x80x94C(O)NR10COR11, xe2x80x94OC(O)R12, xe2x80x94OR13, alkyl, substituted alkyl, aryl, and substituted aryl; wherein when R1 or R2 are selected from group (II), R1 and R2 may optionally form a cyclic structure;
R5, R6, R7, R8, R9, R10, R11, and R12 are H, alkyl, aryl, substituted alkyl or substituted aryl; R13 is alkyl, aryl substituted alkyl or substituted aryl; and
wherein the alkyl and substituted alkyl are C1-C12, and the substituents on the substituted alkyl or aryl contain no functionality which would substantially interfere with free radical polymerization (e.g., groups known to be free-radical chain terminators such as thiols or nitroxides).
It is preferred that R1 be methyl and R2 be H, and most preferred that both R1 and R2 be H. R1 and R2 may also form a cyclic structure when at least one of R1 and R2 are one of the substituents listed above in group II. This may be illustrated in the following structure: 
Alpha-methylene-xcex3-butyrolactone may homooligomerize and homopolymerize. The product of its homooligomerization is a mixture which consists essentially of 
where
m=0-200, n=0-200 and m+n greater than 1;
wherein Y and Z are each independently selected from the group consisting of H, xe2x80x94CH(O), xe2x80x94CN, a halogen, xe2x80x94C(O)OR5, xe2x80x94C(O)NR6R7, xe2x80x94CR8(O), xe2x80x94C(O)OC(O)R9, xe2x80x94C(O)NR11COR11, xe2x80x94OC(O)R12, xe2x80x94OR13, alkyl, substituted alkyl, aryl, and substituted aryl; Y and Z may be combined in a cyclic structure when Y or Z are C(O)OR5, xe2x80x94C(O)NR6R7, xe2x80x94CR8(O), xe2x80x94C(O)OC(O)R9, xe2x80x94C(O)NR10COR11, xe2x80x94OC(O)R12, xe2x80x94OR13, alkyl, substituted alkyl, aryl, or substituted aryl;
R5, R6, R7, R8, R9, R10, R11, and R12 are H, alkyl, aryl, substituted alkyl or substituted aryl; R13 is alkyl, aryl, substituted alkyl or substituted aryl; and
wherein the alkyl and substituted alkyl are C1-C12, and the substituents on the substituted alkyl or aryl contain no functionality which would substantially interfere with free radical polymerization (e.g., groups known to be free-radical chain terminators such as thiols or nitroxides). The depiction of the structures is not meant to imply anything about the arrangement of the monomers along the oligomer backbone.
Alpha-methylene-xcex3-butyrolactone may also co-oligomerize and copolymerize with a variety of monomers and comonomers. These cooligomers would yield products containing  greater than 10% of the following structure: 
where m=0-200, n=0-200 and m+n greater than 1 and where Y and Z and their substituents are as defined above. The depiction of the structures is not meant to imply anything about the arrangement of the monomers along the oligomer backbone.
Preferred comonomers are: acrylonitrile, methacrylonitrile, vinyl methyl ketone, 4-chlorostyrene, 4-chloromethylstyrene, 2,3-dimethylstyrene, 3,4-dichlorostyrene, 4-bromostyrene, 4-hydroxystyrene, 4-methoxystyrene, 4-oxymethylstyrene, 4-bromomethylstyrene, 4-styrenesulfonic acid, sodium salt of 4-styrenesulfonic acid, 4-styrenesulfonyl chloride, methyl acrylate, ethyl acrylate, propyl acrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, dodecyl acrylate, glycidyl acrylate, acrylamide, N,Nxe2x80x2-dimethylacrylamide, bisacrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, acrylic acid, sodium salt of acrylic acid, zinc salt of acrylic acid, acryloyl chloride, [2-(acryloyloxy)ethyl]trimethyl ammonium chloride, 2-ethyloxyethyl acrylate, 2-(N,Nxe2x80x2-dimethylamino)-ethyl acrylate, methacryloyl chloride, methacrylic anhydride, acrylic anhydride, [2-(methacryloyloxy)ethyl]-trimethyl ammonium chloride, 2-(methacryloyloxy)ethyl methacrylate, 2-(methacryloyloxy)ethylacetoacetate, [2-(methacryloyloxy)propyl]-trimethyl ammonium chloride, vinylchloride, 4-vinylbenzoic acid, vinyl acrylate, vinyl methacrylate, vinyl chloroformate, vinyl pyridine, benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, methacrylonitrile, alpha methyl styrene, trimethoxysilylpropyl methacrylate, triethoxysilylpropyl methacrylate, tributoxysilylpropyl methacrylate, dimethoxymethylsilylpropyl methacrylate, diethoxymethyl-silylpropylmethacrylate, dibutoxymethylsilylpropyl methacrylate, diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropyl methacrylate, dibutoxysilylpropyl methacrylate, diisopropoxysilylpropyl methacrylate, isopropenyl butyrate, isopropenyl acetate, isopropenyl benzoate, isopropenyl chloride, isopropenyl fluoride, isopropenyl bromide, itaconic acid, itaconic anhydride, dimethyl itaconate, methyl itaconate, N-tert-butyl methacrylamide, N-n-butyl methacrylamide, N-methyl-ol methacrylamide, N-ethyl-ol methacrylamide, isopropenylbenzoic acid (all isomers), diethylamino alphamethylstyrene (all isomers), para-methyl-alpha-methylstyrene (all isomers), diisopropenylbenzene (all isomers), isopropenylbenzene sulfonic acid (all isomers), methyl 2-hydroxymethylacrylate, ethyl 2-hydroxymethylacrylate, propyl 2-hydroxymethylacrylate (all isomers), butyl 2-hydroxymethylacrylate (all isomers), 2-ethylhexyl 2-hydroxymethylacrylate, isobornyl 2-hydroxymethylacrylate, methyl 2-chloromethylacrylate, ethyl 2-chloromethylacrylate, propyl 2-chloromethylacrylate (all isomers), butyl 2-chloromethylacrylate (all isomers), 2-ethylhexyl 2-chloromethylacrylate, isobornyl 2-chloromethylacrylate, vinylpyrrolidone, and substituted xcex1-methyl-xcex3-butyrolactones of the following structure: 
where R1 and R2 are as defined above, and R3 and R4 are also independently selected from group (I) and group (II), as defined above.
Preferred metallic chain transfer catalysts for use in making the present materials are cobalt (II) and cobalt (III) chelates. Examples of such cobalt compounds are disclosed in U.S. Pat. Nos. 4,680,352, 4,694,054, 5,324,879, WO 87/03605 published Jun. 18, 1987, U.S. Pat. Nos. 5,362,826, and 5,264,530. Other useful cobalt compounds (cobalt complexes of porphyrins, phthalocyanines, tetraazoporphyrins, and cobaloximes) are respectively disclosed in Enikolopov, N. S., et al., USSR Patent 664,434 (1978); Golikov, I., et al., USSR Patent 856,096 (1979); Belgovskii, I. M., USSR Patent 871,378 (1979); and Belgovskii, I. M., et al., USSR Patent 1,306,085 (1986). These catalysts operate at close to diffusion-controlled rates and are effective at part-per-million concentrations. Examples of these cobalt (II) and cobalt (III) chain transfer catalysts include, but are not limited to, those represented by the following structures: 
Co(II)(DPG-BF2)2, where J=K=Ph, L=ligand
Co(II)(DMG-BF2)2, where J=K=Me, L=ligand
Co(II)(EMG-BF2)2, where J=Me, K=Et, L=ligand
Co(II)(DEG-BF2)2, where J=K=Et, L=ligand
Co(II)(CHG-BF2)2, where J=K=xe2x80x94(CH2)4xe2x80x94, L=ligand 
QCo(III)(DPG-BF2)2, where J=K=Ph, R=alkyl, L=ligand
QCo(III)(DMG-BF2)2, where J=K=Me, R=alkyl, L=ligand
QCo(III)(DMG-BF2)2, where J=Me, K=Et, R=alkyl, L=ligand
QCo(III)(DEG-BF2)2, where J=K=Et, R=alkyl, L=ligand
QCo(III)(CHG-BF2)2, where J=K=xe2x80x94(CH2)4-, R=alkyl, L=ligand
QCo(III)(DMG-BF2)2, where J=K=Me, R=halogen, L=ligand
L can be a variety of additional neutral ligands commonly known in coordination chemistry. Examples include water, amines, ammonia, and phosphines. The catalysts can also include cobalt complexes of a variety of porphyrin molecules such as tetraphenylporphyrin, tetraanisylporphyrin, tetramesitylporphyrin and other substituted porphyrin species. Q is an organic radical (e.g., alkyl or substituted alkyl). The preferred Q groups are isopropyl, 1-cyanoethyl, and 1-carbomethoxyethyl.
The chain transfer catalyst herein designated COBF represents the family of chemicals defined by Bis-[(1,2-diR*-ethanedioximato)(2-)O:Oxe2x80x2-tetrafluorodiborato(2-)-Nxe2x80x2Nxe2x80x3Nxe2x80x2xe2x80x3Nxe2x80x3xe2x80x3](A)(B)cobalt(III), where R* is alkyl, aryl or substituted aryl, A is an alkyl or substituted alkyl ligand or an acido ligand (e.g., chloro, bromo), and B is a Lewis base (e.g., water, pyridine. imidazole, phosphine, as well as their derivatives). It is preferred that R* is methyl, A is isopropyl and B is water.
An initiator which produces carbon-centered radicals, sufficiently mild so as not to destroy the metal chelate chain transfer catalyst, is typically also employed in preparing the polymers. Suitable initiators are azo compounds having the requisite solubility and appropriate half life, including azocumene; 2,2xe2x80x2-azobis(2-methyl)-butanenitrile; 2,2xe2x80x2-azobis(isobutyronitrile)(AIBN); 4,4xe2x80x2-azobis(4-cyanovaleric acid); 2-(t-butylazo)-2-cyanopropane; 1,1xe2x80x2-azobis(cyclohexane-1-carbonitrile) and other compounds known to those skilled in the art.
The polymerization process, employing the above described metallic chain transfer catalysts, is carried out suitably at a temperature ranging from about room temperature to about 240xc2x0 C. or higher, preferably about 50xc2x0 C. to 150xc2x0 C. The polymers made by the inventive process are typically prepared in a polymerization reaction by standard solution polymerization techniques, but may also be prepared by emulsion, suspension or bulk polymerization processes. The polymerization process can be carried out as either a batch, semi-batch, or continuous process (CSTR). When carried out in the batch process, the reactor is typically charged with metal chain transfer catalyst, a monomer, optionally with a solvent. To the mixture is then added the desired amount of initiator, typically such that the monomer-to-initiator ratio is 5 to 1000. The mixture is then heated for the requisite time, usually from about 30 minutes to about 12 hours. In a batch process, the reaction may be run under pressure to avoid monomer reflux.
As indicated above, the polymerization can be carried out in the absence of, or in the presence of, any medium or solvent suitable for free-radical polymerization, including, but not limited to, ketones such as acetone, butanone, pentanone and hexanone; alcohols such as isopropanol; amides such as dimethyl formamide; aromatic hydrocarbons such as toluene and xylene; ethers such as tetrahydrofuran and diethyl ether; ethylene glycol; dialkyl ethers such as CELLOSOLVES(copyright) solvent, alkyl esters or mixed ester ethers such as monoalkyl ether-monoalkanoates; and mixtures of two or more solvents.
The oligomers, polymers and/or copolymers prepared according to the present invention can be employed, not only as non-metallic chain transfer agents, but as useful components or intermediates in the production of graft copolymers, non-aqueous dispersed polymers, block copolymers, microgels, star polymers, branched polymers, and ladder polymers.
Aromatic groups formed in poly(xcex1-methylene-xcex3-butyrolactone) and copolymers comprised of xcex1-methylene-xcex3-butyrolactone can be further transformed into amino, nitro, sulfo, and other groups applying well known synthetic methods. See generally J. March, xe2x80x9cAdvanced Organic Chemistry: Reactions, Mechanisms and Structurexe2x80x9d, 4th ed., Wiley Interscience, New York, 1992, p. 641. Such polymers can be used as compatibilizers, surfactants, dispersants, emulsifiers and building blocks in the syntheses of liquid crystals, adhesives. block- and graft-copolymers.
Oligomers, macromonomers and polymers made by the present process are useful in a wide variety of coating and molding resins. Polymers, such as those produced in this invention would find use in, for example, structured polymers for use as pigment dispersants. Other potential uses can include cast, blown, spun or sprayed applications in fiber, film, sheet, composite materials, multilayer coatings, photopolymerizable materials, photoresists, surface active agents, dispersants, adhesives, adhesion promoters, coupling agents, and others. End products taking advantage of available characteristics can include, for example, automotive and architectural coatings or finishes, including high solids, aqueous, or solvent based finishes.